29 Jul
2015
29 Jul
'15
6:52 a.m.
Hi all,
I have experienced this open power control loop a tedious beast when using OpenBTS - it is
a PITA to find settings that work reliably.
Ralph.
-----Original Message-----
From: OpenBSC [mailto:openbsc-bounces@lists.osmocom.org] On Behalf Of Alexander Chemeris
Sent: Wednesday, July 29, 2015 03:26
To: Sipos Csaba
Cc: Ivan Kluchnikov; OpenBSC Mailing List
Subject: Re: Using GPRS
Hi Sipos,
A couple general notes with a remark that I haven't touched the GPRS code for a long
while:
Power control loop for GPRS is separate from the power loop for the CS domain. IIRC it
should be done in PCU, but it's not implemented yet.
So right now IIRC the MS should be in an open loop power control mode, deducing its Tx
power from its Rx level.
I can't comment on the dB values, because I've never used B200. But if you use
fairwaves/master branch, it can detect clipping when the signal is of too high power
(check the logs). You can also enable debug logging level for osmo-trx to assess
demodulation quality visually (there should be few to none '-' in the demodulated
bursts).
If you see the demodulation is perfect, but the issue is still there - you have to dig the
layers upwards.
On Sun, Jul 26, 2015 at 2:02 PM, Sipos Csaba <sipos.csaba(a)kvk.uni-obuda.hu> wrote:
I will try to give you as many feedback as possible.
:-)
I finally have a more or less working setup. At least there is no crash whatsoever, and
the PS domain is working, the UE can attach, activate PDP, transfer data to some extent.
For example when i tried to ping the TUN interface, I got 2500-2600ms latency. I tried
with both the "A" and the "B" algorithm, it was pretty much the same.
I seen a lot of PRACH happening, so I checked the radio parameters:
With power=0 and rxgain=15 at ARFCN=885 I got -55dBm RSSI at the UE, and -40 -45dBm RSSI
at the BTS. The freqency I use is completely clean, and I use a proper duplexer and an
omni antenna. The UE is 2 meters a way, line of site. The SNR measured by the UE is around
20-22 dB in DL direction. The ms-power-loop was set to -15, the max MS power was 20dBm.
So the RF part seems correct, and still I got these very high latencies. In comparison
with OpenBTS and the same setup, I got around 350-500ms latency with multislot.
Maybe the UE goes to IDLE too fast for a ping test?
Regards,
Csaba
----- Eredeti üzenet -----
Feladó: "Ivan Kluchnikov" <Ivan.Kluchnikov(a)fairwaves.ru>
Címzett: "Sipos Csaba" <sipos.csaba(a)kvk.uni-obuda.hu> Másolatot kap:
"Alexander Chemeris" <alexander.chemeris(a)gmail.com>om>, "OpenBSC
Mailing
List" <openbsc(a)lists.osmocom.org> Elküldött üzenetek: Vasárnap, 2015.
Július 26. 14:00:28
Tárgy: Re: Using GPRS
Hi Sipos,
Osmo-TRX master branch should be also fine for gprs, you can use it.
Thank you for report, we will fix osmo-trx fairwaves/master branch soon.
2015-07-26 14:39 GMT+03:00 Sipos Csaba <sipos.csaba(a)kvk.uni-obuda.hu>hu>:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves, Inc.
https://fairwaves.co
Sorry for this last one, GPRS was not enabled in
openbsc.conf.
The PCU is now talking with the SGSN.
But the compilation probem with Osmo-TRX fairwaves/master branch is
still there.
Regards,
Csaba
----- Eredeti üzenet -----
Feladó: "Sipos Csaba" <sipos.csaba(a)kvk.uni-obuda.hu>
Címzett: "Ivan Kluchnikov" <Ivan.Kluchnikov(a)fairwaves.ru>ru>,
"Alexander
Chemeris" <alexander.chemeris(a)gmail.com> Másolatot kap: "OpenBSC
Mailing List" <openbsc(a)lists.osmocom.org> Elküldött üzenetek:
Vasárnap, 2015. Július 26. 12:30:50
Tárgy: Re: Using GPRS
Dear Ivan, Alexander,
I encountered the following issues:
During compiling of OpenBSC (fairwaves/master), the pcap.h was missing.
The configuration script was not detecting this missing file.
"apt-get install libpcap-dev" solved this issue.
The fairwaves/master branch of osmo-trx produces the following issue
durign compilation:
================================
Making all in x86
make[3]: Entering directory `/root/new_openbsc/osmo-trx/Transceiver52M/x86'
CC ../common/convolve_base.lo
CC convert.lo
In file included from convert.c:33:0:
/usr/lib/gcc/x86_64-linux-gnu/4.8/include/smmintrin.h:31:3: error:
#error
"SSE4.1 instruction set not enabled"
# error "SSE4.1 instruction set not enabled"
^
convert.c: In function '_sse_convert_si16_ps_16n':
convert.c:49:3: warning: implicit declaration of function
'_mm_cvtepi16_epi32' [-Wimplicit-function-declaration]
m2 = _mm_cvtepi16_epi32(m0);
^
convert.c:49:6: error: incompatible types when assigning to type '__m128i'
from type 'int'
m2 = _mm_cvtepi16_epi32(m0);
^
convert.c:50:6: error: incompatible types when assigning to type '__m128i'
from type 'int'
m4 = _mm_cvtepi16_epi32(m1);
^
convert.c:53:6: error: incompatible types when assigning to type '__m128i'
from type 'int'
m3 = _mm_cvtepi16_epi32(m0);
^
convert.c:54:6: error: incompatible types when assigning to type '__m128i'
from type 'int'
m5 = _mm_cvtepi16_epi32(m1);
^
make[3]: *** [convert.lo] Error 1
make[3]: Leaving directory `/root/new_openbsc/osmo-trx/Transceiver52M/x86'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/root/new_openbsc/osmo-trx/Transceiver52M'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/root/new_openbsc/osmo-trx'
make: *** [all] Error 2
=================================
Please note that the master branch of Osmo-TRX compiles just fine.
Do any of you have an idea what could be the problem?
Thanks!
Csaba
----- Eredeti üzenet -----
Feladó: "Sipos Csaba" <sipos.csaba(a)kvk.uni-obuda.hu>
Címzett: "Ivan Kluchnikov" <Ivan.Kluchnikov(a)fairwaves.ru> Másolatot
kap: "OpenBSC Mailing List" <openbsc(a)lists.osmocom.org> Elküldött
üzenetek: Vasárnap, 2015. Július 26. 11:35:42
Tárgy: Re: Using GPRS
Thanks Ivan,
Will try that and report back.
Regards,
Csaba
----- Eredeti üzenet -----
Feladó: "Ivan Kluchnikov" <Ivan.Kluchnikov(a)fairwaves.ru>
Címzett: "Sipos Csaba" <sipos.csaba(a)kvk.uni-obuda.hu> Másolatot kap:
"Alexander Chemeris" <alexander.chemeris(a)gmail.com>om>, "OpenBSC
Mailing
List" <openbsc(a)lists.osmocom.org> Elküldött üzenetek: Vasárnap, 2015.
Július 26. 10:56:51
Tárgy: Re: Using GPRS
Hi Sipos, Omar,
You should use the following branches:
libosmocore branch master
libosmo-abis branch master
osmo-trx branch fairwaves/master
osmo-bts branch fairwaves/master ( use ./configure --enable-trx)
openbsc branch fairwaves/master
osmo-pcu branch master (use ./configure --enable-sysmocom-bts )
openggsn branch master
Also if you use the same machine for sgsn, bts and pcu, you should
change openbsc.cfg, instead of:
gprs nsvc 0 local udp port 23000
gprs nsvc 0 remote udp port 23000
use different ports, for example:
gprs nsvc 0 local udp port 5948
gprs nsvc 0 remote udp port 23000
--
Regards,
Ivan Kluchnikov.
http://fairwaves.ru
--
Regards,
Ivan Kluchnikov.
http://fairwaves.ru